Successive governments have been committed to reducing reoffending. A policy is currently being pioneered to reward regimes that can prove that they have reduced reoffending.

The problem lies in how you measure the outcome when you decide to pay by results. It is notoriously difficult, not least because it depends on measuring a negative – at what point do you measure and reward non-offending after a year, or two, or three or five years of not offending again.

Everyone agrees that there are many factors that shape behaviour. That is true of us all, and it is also true of offenders. In having a family, especially a child, the prospect of a job and somewhere to live all form a strong motivation to get out and stay out of prison. Those are the lucky ones.

However, many prisoners suffer from one or more mental illnesses. As with the mentally ill on the outside, so on the inside, people’s moods are affected by relationships and environment.

Unfortunately, this lack of understanding in the media about the degree of mental illness among offenders leads to an unbalanced public debate about conditions in prison.

Creative, purposeful activity where prisoners see a return on their labour encourages a positive attitude for themselves. Working in a garden or a workshop where they learn a skill and get paid builds up self-esteem, which is key to raising aspirations to make a go of life outside.

Punishment in prison is the deprivation of liberty. Its purpose is to change behaviour, but incarceration must avoid imprisoning offenders in a downward spiral of self-hatred. Connecting them with the dynamic of life and growth through gardens and farms can break the cycle of violence and despair.

I remember seeing a woman prisoner, who had no meaningful relationship with anyone, coming out of her damaged self through the caring for an animal in prison.

If people are sent to prison to reinforce their low self-esteem and to learn criminal skills, it is society that is badly served. Criminals do deserve to be punished and society also deserves to be protected, not just from present but future harm.

Rt Rev. James Jones, the Lord Bishop of Liverpool, is a bishop for prisons, visitor to St Peter’s College in the University of Oxford, and co-president of Liverpool Hope University.

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